Analytical balance



Dec. 1, 1931. A

WITNESS:

J. F. KRAYER ANALgTICAL BALANCE Filed Jan. 10. 19:51

2 Sheets-Sheet l D- 1, 1931 y J. ii KRAYER 834,848

' ANALYTICAL BALANCE Filed aani 1o, 1931 4 2 sheets-sheet 2 INVENTOR ATTORNEY Patented Dec. 1, 1931 `v UNITE l j JDHNKRAYEIMOF FLUSHING, NEW YORK n ANALYTCAL BALANCE Animation,ni'avianearyio; 193i. seriai NQ.V 507,920.1"

` f This invention relatesy to precision Weigliing instruments, and imore particularly lto balances as used' 'in analyticalchemistry',

assaying and the like.

' 5 l"Analytical"andassaybalancesas at present v l measurement of extremely light Weights. In

the use of such balances; it has-been' found that the beamy and-thieindicator have been subj ect to oscillation from' one' `direction to another; Wlienthe balance isI inuse,` tHe-'frequency ofthe oscillations bei-ng ysuch that a considerable length ottime has'elapsed before' the pointer or 'indicator has' cometoitls point' oil rest on' the scale. j j f 5 1 Them primary object of the present inven tion is to enable an analytical or'V assay balance and* the' like to come? to rest' without appre` ciable oscillation ofthebeam and pointer, theA oscillationsbeing eifect'ively damped; so that' j the balance Will be quick acting`,f"tlifereby ref-- sultinginv aai-appreciable saving f of time; and

greater accuracy in the use of the balance;

f Another object oftlieY invention is toprovide- "anal-'ytie'al''or1 assay-balance Withj shoclrfabsorbingwineans'V inf the forni of air cushion devices Whiclifinclude aL Vmovablecuporl the likev carried 'at each end vof tlrebeam; each`` offA these cupscooperating with `a pair of' st'ationaryE concentric l cups' being' adapted toiform anqair cushion; Without physicalcon- 4o'V tact-between the movingparts;tlierconstruc;`

tion beingsuclrtliat the cushioningfetfect is greater during-the latter partf'ofthe dovvn-A Ward" swiii'g of"V each fofthe beamV ends than duringl the earlyf pa-rt "o'suclij svs'fing;y tlie` V cusl'iioningdevice for t-he opposite-endof the beam 'being' adapted to `exenta-E cooperative" cushioning effect, whereby theI bea-m Will be caused to come to 'restpra'ctically WithoutA anyl oscillation,. thus-enabling the `user`ito obtain quiclivand acouratereadin'gf, and

avoiding the llikelihoodv of the user taking a reading vWhile vthe pointer is oscillating very short distances apart. Y v j Aurther object ofthe invention isfto prove thefconstruction andl 4operation'of the graduated scale which operates in conjunc'- tionfvvithy the indicator or pointer, whereby c the scale vvillfin'clude a vernier adjustment, including a movable scale having a greater l number of fractionalparts in each'l oif'its di- 66? visions than in `onedivision of the fined scale, wherebyv an accurate vernier reading'is quick# ly obtainable.,

` A` still further objectisto provideacush'-` j* i ioning equipment Whichis readily applicable tofstandard'types of balances at present in use,bysirnple attachment of the-"cushion`ing -inean'sfto the column or otherstandardosupport for the balance. v j n j y i y Ot'her'objects' and advantag'S Ofwthelini0 vention Willbe hereinafter specficallyy point"-l fication proceeds. Y

yed out, or Will become apparennxas the speci` Y Wah the above inaieaedrobjeefjs infvew; the' invention resides in certain novel con-v 75'" structions and-combinations and arrangement of partsfclearly described in following specification a'ndfully illustrated intliejf accomp anying drawings', which lattershovv1 cfmboldiments of'the'f invention as' atl'present' pre-V l80 ferred:A Y 5 In the drawings: j f` Y 1 i Fig. l1` is a front elevation, partly in section,

of atypical analytical balance, showing the. l

present improvements applied thereto; 8'5 Fig. 2 is4 av transverse sectional vievv through the apparatus as shown in Eigql; taken slib-V ingin the direction ofthe arrows; j j ,l Fig; 3 is an enlarged-detail vsectional view' 9'0' through one of theV cushioningrdevi'ces, taken on the line 3- -3 of Fig,`2; looking' in thel direction of the arrows;

v Fig-4 isa perspective view Fig. 5-is a perspectiv'eview of the movablefscalewhich cooperates the' fixed n scale oFig '4; t0 provide'the Vernier ad-y justment; and i of the Vfixer Fig: '6'y is a perspective vievv o'ncof the 166 bracket members for supporting the cushioning means upon the column of a standard balance.

The invention, in this instance, is shown in connection with a conventional type of analytical balance, which includes a swingable beam supported upon a column 11 by means of a central knife edge 12, the opposite ends of the beam having knife edge supports 13 and 14 for a pair of hooked rods or joints 15 and 16, respectively, from which latter are suspended two pairs of bows 17 and 18, respectively, which pairs of bows carry the usual pans 19 and 20. V

To cushion the swinging movement of the beam I provide, in this instance, a shock absorbing or oscillation damping attachment, which, in this instance, is adapted to be mounted upon the column 11 of the balance, but which may be otherwise mounted if desired. rlhis attachment, as shown. includes a horizontal bar A21 adapted to be fixedly secured to a horizontal bracket 22, mounted on the column 11. `This bracket 22 includes two similar half portions 23, each of which has a rounded portion 24 to embrace one side of the column, and an elongated rearwardly extending portion 25. The two bracket halves 23 are secured together about the column 11 by suitable rivets 26 which extend through aligned holes 27 in the meeting bracket portions 25. Each of the bracket portions is provided, at its free end, with a vertical semicircular recess 28 which together produce a cylindrical aperture for reception of a screw of the like 29 by which the bar 21 is secured to the bracket 22.

The bar 21 is thus supported in the paiallel plane of the beam `10, and preferably to the rear thereof, the end portions 30 and 31 of the bar terminating substantially in the vertical plane of the respective beam ends.`

A kpair of arms 32 and 33 are mounted horizontally on theV beam ends 30 and 3 1, respectively, and means are provided so thatthe forward ends of the arms 32 and 33 may be positioned substantially in .the axial planes of the respective beam ends. For this latter purpose the arms 30 and 31 are preferably provided with elongated slotted portions 34 and 35, respectively, and the arms 32 `and 33 have .similar slottedportions 36 and 37, respectively. Thumb screws or similar fastening devices 38 aud 39, respectively, are passed through the slots 34, 36 and 35, 37, to secure thearms 32 and 4in the proper adjusted position upon the bar.

lhe cushioning means proper include, in this instance, a pair of cushioning devices 40 and 41, one for each end of the beam. Both of these cushioning devices are alike in construction, so that a description of one will suilice for the other. As seen in detail in Figs. 1 and 3, each cushioningdevice includes n a pair of concentric open top cups, including an outer cup 42 and an inner cup 43, the outer cup 42 being of greater height than the inner cup 43, there being a small clearance between the walls 44 and 45 of the respective cups. The cups 42 and 43 are secured to the end of the arm 32 (or 33, as the case may be) by means of a suitable rivet or other fastening means 32. The cups 42 and 43 are thus rigidly mounted in stationary relation to the swingable beam.

A third cup 46 is inverted over the inner cup 43, the lower or open portion of the cup 46Y being adapted to surround the wall 45 `of the inner cup 43, the inverted cup 46 being suitably mounted to be carried by the beam so that the side wall 47 of the cup 46 will traverse the annular space 48 between the walls 44` and 45 of the stationary cups 42 and 43. The wall 47 oi the cup 46 is desirably of about the same height as the wall of the cup 43, but less than the height of the wall 44 of the outer cup 42. To inovably support the cup 46 a supporting rod 49 is preferably secured to the bottom portion 50 of the inverted cup 46, the lower part of the rod 49 being preferably provided with screw threads 51 and being adapted to be secured in different adjusted position by means of suitable lock nuts or the like indicated at 52 and 53.y The upper end of the supporting rod 49 is equipped with a hook portion 54 by which the respective cushioning devices 4() and 41 are secured to the hooked rods 15 and 16 which are suspended from the opposite beam ends. The outer cup 42 is preferably provided with a removable cover 55, and this cover is provided with anjaxial aperture 56 through which the rod 49 extends. The aperture 56 is preferably of such size that substantial clearance will be afforded for the rod 49, so that there will be no physical contact between any of the relatively movable parts of the cushioning devices during swinging of the beam, and also so that air may be admitted and exhausted through the aperture 56. l

During swinging of the beam in a downward direction, the air trapped between the inner cup 43 and the inverted cup 46 will act as a sensitive air cushion, while, at the opposite or upwardly swinging end of the.

am a reverse cushioning effect will occur between the inverted cup and the stationary cups as air is permitted to exhaust fromr the interior of the cup 43, through the annular passage 48. and out through the axial aperture 56. Since the oscillations of the beam are of very slight strength, due to the sensitiveness of the balance, the air cushioning effeet obtained is also very slight, yet suiicieni .to restrain the oscillation of the beam ends practically instantaneously, so that the indicator pointer 57, and, as well, any other indicating devices carried by the balance, will come to rest practically instantaneously.

I also provide, in@ this instance, improved"V ably beingprovided with-an operatingknob.i

` lTo obtain a very fine and accurate-reading,

means for obtaining kajverni'er;` adjustment lot the'y scale with which* the indicator-1pointer4 57 cooperates,,whereby to obtain a;.venyaccurate` reading.v

Thestationary-scale'58 includesin this in-.l

stance, a plate 59-suitably secured tothe base portion 60 of the colummas for instanceby means of; screws 61 which extend throughv ap-V ertures .62 ,provided infthescale plate 59, Aandf into the base. portion 60:; This stationary scale plate 59 is provided; with arcuately arfranged graduations laid` out in; a, plurality of,

divisions.63, .64', 65T` and 66,. anyydesiredgnumber: of divisionsbeingprovidedr Each of the divisionsis of equal length and includes-the samenumber of fractional parts or subdie visions67, having any specifiedV value, such,

for instance, as one milligram.4

. The-indicator pointer -57"may ordinarily cooperate with the* graduations ofthe` stationary scale 58, but, foriine; adj ust-mentpun p.oses,andY to. secure verfyaccurate fractional;` readings, I provide, inthis instance, a mov-` able scale 68 to cooperate withy the stationary scale 58. 'I his movable `stale: G8 includes. an

elongated arouately formed bo dyy orba'seportion 69'and an upstanding--graduatedI portion 70. The base portion (iQ-has. an elongated slot 71, and, the stationary' scale 58z is provided withzapair of pins on similardevices 72 which extend, through the slot` 71to movablysupport the scale 68 upon the scale` plate-59, the.

outer. ends. ofthepins 7 2 being preferably upset., or headed,.or being.y otherwise equipped to .iietainthezmovable scale-687m place.` i

Thenpstanding portion 70 ot themovable scale is. provided with graduations, -inthisinstance laid;y outintwo divisions 7 3 and 7,4, of equal. length. Each oi` the divisions 7.3 and 74 is provided with. alike number of fractional. parts or subdivisions7`5, having-V suitable indicia 7G\ reading from, thezero,

point 77 between thedivisions 73 and 74. In this instance, the ractionalgparts orsubdivisions .of the movable scale divisions are pro-V vided to a number greater than the fractional.- parts of the stationary scaleV divisions,

. which fractionalpartsof the stationaryscale divisions liaveffthe same length as the ractional parts of the` ymovable' scale divisions.

That is tosay, inv thisinstance, iivefractional subdivisions. of the movable scalefarepequal in lengthto four i'ractionalj parts or 'subdivisions of one ofthe stationaryscale divisions; Y i. l l

Means aieprovided to movethe movable scale to a, positioniso that its. Zero point 77` willA coincide with the restqaosition.y of the. pointer orindicator 5G on the stationary scale plate' 59. In this instance the base portion G9. ot the movable scale is equipped .withan elongated rod 78 which may extend .outward to a side ofthe casing or other enclosure fior l thebalance, the outer end ofthey rod pieten.

the stationary scale fractional subdivisions,

in accordance with standard vernierpractice, thus enablingthefuser to obtain a very rapidiand accurate scale reading. .l

Considerable particularities ot description, as (to, materials,y part details, dimensions, caf

pacities and utilities may have been herein-r indulged in, but it willpbe understood thatr these statements, made with particular ref-V erence tothe embodiments of the invention. illustrated in the drawings, are not in any way to bejtalen as dei'init'ive or limitative ofy theinveiition. Inasmuch as many changes could be made in theabove construct-ions, and" many apparentlyy widely different'embodiments ci' the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or vshown in the accoin-y panying drawings shall be interpreted as il-` lustrative-andnot in a lii'niting sense.` y

It is .also to bey understood that the language contained in the following claims is intended to .Coverall the generic and specific features of the invention herein described, and. all statements 'of the scope of the'invention which, as a matterfo't language, mightbe said toy fall therebetween. y

pende-d claims,` interpreted asvbroadlyas is consistent with the prior art.- y

What I claim is:

Al. The combination with anfind-icating bal-A ancehaving a swingable beainvand a supporting; column therefor, .oianair cushioning attachment for .damping the oscillations; of

said beam, said air'cushioning attachment including a .pair of devices each ,including a pair of opentop concentric cylindrical stay tionaryfcups, means to `rigid-ly support said pair oi stationary cups beneath opposite ends In other words., the scopeof protectioncon-l. templated is to be taken solely from the apk k ot said beam, a movableinverted cup member concentric with each-p air of said open top cups, f

thewall of said. inverted cup traversing the annular space betweenthe walls of said open topcups, means to support said invertedr cups atA opposite l ends otsaidxbeam', the Voutermost open-top cup having. removable closure, said closurehaving an axial .hole for passage of said rod `andfory air'intale and exhaust,

fand means tor-,adjusting the travel of said inverted cup.

ance having a swingable-ebeam andra support- 2. The combination with anindicating bal-.

fing column therefor, of an air cushioning :attachment for damping the oscillations of 'said beam, said air cushioning attachment including a pair of devices each including a pair of open top concentric cylindrical stationary cups, means to rigidly support said pairs of stationary cups upon said column, a movable inverted cup member concentric with each pair of said o pen top cups, the wall of said invert-ed cup traversing the annular space between the walls of said open top cups, a rod axially secured to said inverted cup, each end of said beam having a suspension member, each of said rods having a hook portion for attachment to one of said suspension members, the outermost open-top cup having a removable closure, said closure having an axial hole for passage of said rod and for air intake and exhaust, said rod including a screw threaded portion affording means for adjusting the travel of said inverted cup.

3. The combination with an indicating` balance having a swingable beam and a supporting column therefor, of an air cushioning` attachment for damping the oscillations of said beam, said air cushioning attachment including pair of devices each including a pair of open top concentric cylindrical stationary cups, an arm to which said pair of cups are secured, an elongated bar adjustably connected at each of its opposite ends to one of said arms, a bracket secured to said bar, said bracket including a pair of column engaging members, a movable inverted cup member concentric with each pair of said open top cups, the Wall of said inverted cup traversing the annular space between the walls of said open top cups, `means to support said inverted cups atv opposite ends of said beam the outermost open-top cup having a removable closure, said closure having an axial hole for passage of said rod and for air intake and exhaust.

4. The combination with an indicating balance having a swingable beam and a supporting column therefor, of an air cushioningattachment for damping the oscillations of said beam,said air cushioning attachment including a pair of devices each including a pair of open top concentric cylindrical stationary cups, an arm to which said pair of cups are secured, an elongated bar adjustably lconnected at each of its opposite ends to one of said arms, a bracket secured to said bar, said bracket including a pair of column engaging members, a movable inverted cup member concentric with each pair of said open top cups, the wall of said inverted cup traversing the annular space between the walls of said open top cups, a rod axially secured to said inverted cup, each end of said beam having a suspension member, each of said. rods having a hook portion for attachment to one of said suspension members.

5. The combinationr with an indicating balance having a swingable beam and a supporting column therefor, of an air cushioning attachment f-or damping the oscillations of said beam, said air cushioning attachment including a pair of devices each including a pair of open top concentric cylindrical stationary cups, an arm to which said pair of cups are secured, an elongated bar adjustably connected at cach of its opposite ends to one of said arms, a bracket secured to said bar, said bracket including a pair of column engaging members, a movable inverted cup member concentric with each pair of said open top cups, the wall of said inverted cup traversing the annular space between the Walls of said open top cups, a rod axially secured to said inverted cup, each end of said beam having a suspension member, each of said rods having a hook portion for attachment to one of said suspension members, the outermost open-top cup having a removable closure, said closure having an axial hole for passage of said rod and for air intake and exhaust, said rocL including a screw threaded portion alfording means for adjusting the travel of said inverted cup. n

G. The combination with a balance and the like having a swingable beam and an indicating` pointer, of an indicating scale including a stationary graduated scale associated with said indicating pointer, a movable scale associated with said stationary scale` both of said scales having divisions of equal length, each division of said movable scale having a different number of fractional parts when the fractional parts of cach division of the statimiary scale, said stationary scale inclu ding means to slidably support said movable scale, and an operating .rod pivotally secured to said movable scale for manipulation of said movable scale to different positions whereby the zero point of said movable scale coincides with the rest point of said indicator pointer on said stationary scale, to indicate fractional parts of one of the equal fractional parts of one ef the stationary scale divisions.

7. The combination with a balance and the like having a swingable means and an indicating pointer, of an indicating scale in cludingr astationary graduated scale associated with said indicating pointer, a movable scale associated with said stationary scale, both of said .cales having divisions of equal. length, each division of said movable scale havinga greater number of fractional parts than the fractional parts of each division of the stationary scale, said movable scale having an elongated slot, said stationary scale including a plate having a plurality of devices traversing said slot and seclniing the stationary and movable scales together in operative relationship, and an operating rod pivotally secured to said movable scale for manipulation of said movable scale to different positions whereby the zero point of said movable scale coincides with the rest point of said indicator pointer on said stationary scale, to indicate fractional parts of one of the equal fractional parts of one of the stationary scale divisions.

8. The combination with a balance and the like having a swingable beam and an indicating pointer, of an indicating scale including a stationary graduated scale associated with said indicating pointer, the graduations of said stationary scale being arcuately arranged, a movable scale associated with said stationary scale, both of said scales having divisions of equal length, each division of said'movable 's calehaving a different numbei' of fractional parts than the fractional parts of each division of the stationaryfscale, said movable scale including an elongated base having an elongated slot, said stationary scale including means traversing said elongated slot and securing the stationary and movable scales together in operative relationship, and an operating rodv pivotally secured to the base portion of said movable y scale for manipulation of said movable scale to different positions whereby the Zero point of said movable scale coincides with the rest point 'of said indicator pointer on said stationary scale, to indicate fractional parts of one of the equal fractional parts of one of the stationary scale divisions. Y

9. The combination with a balance and the like having a swingable beam and an indi-j. s eating pointer, of an indicating scale includ' ing a stationary graduated scale associated with said indicating pointer, the graduations or said stationary scale being arcuately arranged, a movablefscale associated with said stationary scale, both of said scales having divisions of equal length, each division of said movable scale having a greater number of fractional parts than the fractional parts of each division of the stationary scale, said movable scale including anfelongated base having an elongated slot, said stationary scale including a plate having -a plurality of pins traversing said elongated slot and securing the stationaryv and movable scales together in operative relationship, and an operc ating 'rod pivotally secured tothe base portion of said movable scale for manipulationof said movable scale to different positions whereby the zero vpoint of said movable scale coincides with `the rest point of said indicator pointer on said stationary scale, to indicate fractional parts of one of the equal fractional parts of one of the stationary scale divisions.

In testimony whereof I hereby `affix my signature.

JOHN F. KRAYER. 

